The inventions described in this specification concern a number of improvements to the design of thermally insulating glass panels. These panels typically comprise two spaced apart sheets of glass enclosing a low pressure space and interconnected by an edge seal and an array of support pillars. The panels are used for glazing, and such thermally insulating windows are generally referred to as evacuated glazing.
Thermally insulating panels are typically constructed by depositing a strip of solder glass around the periphery of the glass sheets; depositing an array of support pillars onto one or other of the sheets of glass; bringing the sheets together or permitting them to move together; heating the panels to melt the solder glass around the periphery so that the two sheets settle onto the pillars; and then cooling the panel to solidify the edge seal. The panel is then evacuated by pumping out through a tube positioned either through one of the glass sheets or through the edge seal, and finally the pump-out tube is melted and sealed off.